Case 1: You CANNOT raise a double precision number to a power such that it exceeds flintmax (2^53 - 1) and expect the result to be correct.
And that means when you execute this:
you should expect pure garbage if you expect the result to have correct digits.
Case 2: While you MAY think that -2^31 raises the number -2 to a negative power, in fact, it forms 2^31, and then negates that result. If the power is odd, then this does not matter, because the negative sign works then. But if the power is even, then it does matter.
Raising a number to a power has a higher order of precedence than does unary minus. So these two operations are not the same:
I used an even power to show they are distinct there.